Phosphorus removal from aqueous solution in parent and aluminum-modified eggshells: thermodynamics and kinetics, adsorption mechanism, and diffusion process

Enrichment of Total Flavonoids and Licochalcone A from Glycyrrhiza inflata Bat. Residue Based on a Combined Membrane-Macroporous Resin Process and a Quality-Control Study

Glycyrrhiza inflata Bat. produces a lot of licorice waste after water extraction, which also retains abundant total flavonoids (TFs) and licochalcone A. However, licorice residue is often wasted due to the lack of good utilization of resources in practical applications. This study first screened the optimal membrane pore size and resin type and then explored the mechanism and conditions of the adsorption of TFs on the resin. Then, different combinations and sequences of membrane and macroporous resin (MR) methods were investigated. It was found that using the membrane method for initial purification, followed by the MR method for further purification, yielded the best purification results. Next, response surface methodology was utilized to investigate the resin's dynamic desorption conditions for TFs. Finally, the TF purity increased from 32.9% to 78.2% (2.38-fold) after purification by a combined membrane-MR process; the purity of licochalcone A increased from 11.63 mg·g-1 to 22.70 mg·g-1 (1.95-fold). This study verified the feasibility of enriching TFs and licochalcone A from licorice residue using a membrane-MR coupling method. In addition, a quality-control method was established using a fingerprinting method on the basis of ultrahigh-performance liquid chromatography (UPLC) to ensure the stability of the enrichment process.

Continuous treatment of highly concentrated tannery wastewater using novel porous composite beads: Central composite design optimization study

This present study depicts the successful employment of fixed-bed column for total chromium removal from tannery wastewater in dynamic mode using sodium alginate-powdered marble beads (SA-Marble) as adsorbent. The SA-Marble composite beads prepared were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and Brunauer, Emmett and Teller (BET) method. The adsorption process performance of this bio-sorbent was examined in batches and columns for real effluent (tannery wastewater). After 90 min, the total chromium removal efficiency could be kept above 90% in the batch experiment. The adsorption kinetics fit better with the pseudo-second-order model, indicating the chemisorption process and the adsorption capacity of about 67.74 mg g-1 at 293 K (C0 = 7100 mg L-1) was obtained. Additionally, dynamic experiments indicate that the total chromium removal efficiency could be maintained above 90% after 120 min at 293 K and 60 min at 318 and 333 K; it's an endothermic but rapid process. The effects of two adsorption variables (Temperature and time) were investigated using central composite design (CCD), which is a subset of response surface methodology (total Cr, COD, sulfate, and total phosphorus percentage removal). This work paves a new avenue for synthesizing SA-Marble composite beads and provides an adsorption efficiency of total chromium removal from tannery wastewater.

Graphical abstract

Characterisation of kapok fibre's biochar for arsenate adsorption removal from aqueous solution

Al-KBC was produced through the simple pyrolysis of Al-modified kapok fibres at high temperatures. Using the N₂ adsorption Brunauer Emmett Teller (BET) process, Fourier transforms infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), the energy-dispersive X-ray spectroscopy (EDS) spectroscopy, and X-ray photoelectron spectroscopy (XPS), the sorbent changes and characteristics were analysed. As a result of Al's addition to the fibre's surface, Al-KBC exhibited superior As(V) adsorption performance compared to KBC due to better pore structures. Experiments on the kinetics of As(V) adsorption revealed that the adsorption followed the pseudo-second-order model and that intradiffusion was not the only factor governing the adsorption. Experiments with isotherms indicated that the adsorption mechanism corresponded to the Langmuir model, and the adsorption capacity Q_m of Al-KBC at 25 °C was 483 μg/g. The thermodynamic experiments suggested that the adsorption reactions were spontaneous endothermic with a random approach at the adsorption interface. 25 mg/L of coexisting ions such as sulphate and phosphate reduced the sorbent As(V) removal ability to 65% and 39%. After seven cycles of adsorption/desorption, Al-KBC demonstrated satisfactory performance in terms of reusability, adsorbing 53% of 100 μg/L As(V) from the water. This novel BC can probably be used as a filter to purify groundwater with high As(V) concentration in the rural zone.

Fast arsenate As(V) adsorption and removal from water using aluminium Al(III) fixed on Kapok fibres

Arsenic (As) is among the most dangerous metalloids and is harmful to human wellbeing. In this laboratory study, Al(III)-modified kapok fibres (Al-Kapok) were used to remove As(V) from water. The sorbent was characterised using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX). Batch experiments were performed to observe the performance of Al-Kapok in the removal of As(V) and to examine the effects of pH, temperature, adsorbent dose, and coexisting ions on the adsorption process. The surface of the sorbent changed after aluminium modification, and the results of the batch experiments showed that the adsorption of As(V) occurred mainly via endothermic-spontaneous chemisorption at the solution and solid interface of Al-Kapok. The As(V) removal efficiency was approximately 76%-84%, and it was slightly affected at pH levels below 8.0. Further study showed that the maximum adsorption capacity of Al-Kapok for As(V) was 118 μg/g at 30 °C and pH 6, and notable adverse effects were caused by the presence of SO₄^2-and PO₄^3-. It was also found that the boundary layer and film diffusion contributed more to As(V) adsorption. After five adsorption/desorption cycles, regeneration recovered approximately 92% of the adsorption capacity of Al-Kapok used. Overall, Al-Kapok appears to be a suitable adsorbent material for the purification of As-contaminated water.

From wastes to functions: preparation of layered double hydroxides from industrial waste and its removal performance towards phosphates

To control eutrophication and recover phosphate from wastewater, a calcium carbide slag and red mud composite material (CR-LDH) was prepared using industrial waste as raw material for phosphorus adsorption. The morphology and structure of synthesized CR-LDH were characterized by FT-IR, SEM, EDS, and XRD measurements. Bath adsorption test results showed that the optimal dosages of adsorbent and pH for phosphate were 5 g·L^-1 and pH of 7, respectively. The experimental data could be well described by pseudo-second-order kinetic and Langmuir isotherm models, suggesting that the adsorption process of CR-LDH with respect to phosphate was a chemical and monolayer process. The theoretical maximum adsorption capacity obtained by Langmuir isotherm model was 16.06 mg·g^-1 at 25 °C. The intra-particle diffusion model fitting results indicated that the adsorption of phosphate by CR-LDH was controlled by both liquid membrane diffusion and intra-particle diffusion. Phosphate was bound to CR-LDH via synergistic effect of physical adsorption, ion exchange, anion intercalation, and chemical precipitation as evidenced from a combination of microscopic analysis and adsorption mechanism study. The actual phosphate-containing wastewater investigation showed that CR-LDH not only exhibited good removal effect on phosphate, but also could greatly reduce turbidity, COD, and ammonia nitrogen, which was suitable for disposal of practical wastewater. The COD, turbidity, and NH₄⁺-N could be reduced by 42.39%, 77.20%, and 20.71%, respectively. These results indicate that CR-LDH can be considered as potential adsorbent for the treatment of phosphate-containing wastewater, which will be helpful to achieve the goal of "treating waste with waste and turning waste into treasure".

From wastewater to fertilizer products: Alternative paths to mitigate phosphorus demand in European countries

Phosphorus (P) is a non-renewable resource, irreplaceable for life and food production, and currently considered a Critical Raw Material to the European Union (EU). Due to concerns about the rate of consumption and limited reserves in countries with sensitive geopolitical contexts, it is urgent to recover P from urban and industrial flows. Indeed, the municipal wastewater treatment plants (WWTP) are considered relevant sources with several hot spots, especially sewage sludge with estimated recovery efficiencies of >80%. The most promising recovery strategies are based on thermal treatments (e.g., incineration of sludge) following by wet-chemical or thermo-chemical leaching, precipitation, and adsorption. The direct application of sludge on soil is no longer a primary route for P reintegration in the value-chain for countries as Switzerland, Germany, and The Netherlands. In fact, Switzerland and Austria paved the way for implementing P recovery legislation, focusing on recovery from raw sewage sludge or ashes. Indeed, industrial technologies with sludge ash as input show high recovery efficiencies (Ashdec® and Leachphos® with 98 and 79%) and lower environmental impacts, whereas Pearl® technology has about 12% recovery efficiency with wastewater as input. After all, struvite emerges as the most recovered product with recent access to the internal market of EU fertilisers and similar growth performance compared to triple-super-phosphate. However, several studies leave open the possibility of introducing loaded adsorbents with P as soil amendments as a new alternative to conventional desorption. Briefly, P recovery should be a compromise between efficiency, environmental impacts, and economic revenues from the final products.

Adsorption and Desorption Characteristics of Total Flavonoids from Acanthopanax senticosus on Macroporous Adsorption Resins

We examined the application of six different resins with the aim of selecting a macroporous resin suitable for purifying Acanthopanax senticosus total flavonoids (ASTFs) from Acanthopanax senticosus crude extract (EAS) by comparing their adsorption/desorption capacities, which led to the selection of HPD-600. Research on the adsorption mechanism showed that the adsorption process had pseudo-second-order kinetics and fit the Freundlich adsorption model. Moreover, the analysis of thermodynamic parameters indicated that the adsorption process is spontaneous and endothermic. The optimal conditions for purification of ASTFs were determined as sample pH of 3, 60% ethanol concentration, and 3 BV·h⁻¹ flow rate, for both adsorption and desorption, using volumes of 2.5 and 4 BV, respectively. The application of macroporous resin HPD-600 to enrich ASTFs resulted in an increase in the purity of total flavonoids, from 28.79% to 50.57%. Additionally, the antioxidant capacity of ASTFs was higher than that of EAS, but both were lower than that of L-ascorbic acid. The changes in ASTFs compositions were determined using ultra-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS), with the results illustrating that the levels of seven major flavonoids of ASTFs were increased compared to that in the crude extract.

Phosphate removal from food industry wastewater by chemical precipitation treatment with biocalcium eggshell

The physicochemical treatment (PT) of food industry wastewater was investigated. In the first stage, calcium magnesium acetate (CaMgAc₄) was synthesized using eggshell (biocalcium), magnesium oxide and acetic acid in a 1:1:1 stoichiometric ratio. In the synthesis process, the thermodynamic parameters (ΔH, ΔS and ΔG) indicated that the reaction was endothermic and spontaneous. The samples were characterized by infrared spectroscopy (IR), scanning electronic microscopy (SEM), X-ray diffraction (XRD) and electron X-ray dispersive spectroscopy (EDS). CaMgAc₄ was used to precipitate the phosphate matter. IR analysis revealed that the main functional groups were representative of the acetate compounds and the presence of OH^- groups and carbonates. In the physicochemical treatment, a response surface design was used to determine the variables that influence the process (pH, t, and concentration), and the response variable was phosphorus removal. The treatments were carried out in the wastewater industry with an initial concentration of 658 mg/L TP. The optimal conditions of the precipitation treatment were pH 12, time 12 min, and a CaMgAc₄ concentration of 13.18 mg/L. These conditions allowed the total elimination (100%) of total phosphorus and phosphates, 81.43% BOD₅ and 81.0% COD, 98.9% turbidity, 95.01% color, and 92% nitrogen matter.

Covalent organic framework EB-COF:Br as adsorbent for phosphorus (V) or arsenic (V) removal from nearly neutral waters

The covalent organic framework (COF) is made light elements linked by covalent networks. This study synthesize and characterized, and for the first time applied the produced EB-COF:Br as adsorbent for phosphate and arsenate removal from nearly neutral waters. The synthesized COF was first proven structurally stable in solutions of 75% H₃PO₄, 6 M HCl, or 6 M NaOH. Then the phosphate adsorption onto the EB-COF:Br was shown to be an endothermic process with maximum adsorption capacity at 25, 35 and 45 °C as 25.3, 34.7 and 35.3 mg/g COF, respectively; and the corresponding arsenate adsorption process being an exothermic process with maximnum adsorption capacity as 53.1, 27.5 and 5.1 mg/g, respectively. The synthesized COF could also effectively adsorb phosphate and arsenate ions from river water (pH 7.45) but at reduced adsorption capacities. The electrostatic interactions between the negative charge on phosphate or arsenate ions and the positively charged (N⁺-) of COF, and the hydrogen bondings between H atom on phosphate or arsenate ions and the (-CO) group of COF were the dominating mechanisms for the present adsorption process. The strong electrostatic interactions for arsenate contributed to its higer adsorption capacity than noted for phosphate at 25 °C. However, the disturbed hydrogen bonding induced by mismatched sizes of arsenate ion and the adsorption sites surrounded by the (N⁺-) and the (-CO) groups reduced the stability of arsenate to against temperature and external anion challenges. The use of the EB-COF; Br as industrial adsorbent was also discussed.

Phosphorus removal from secondary wastewater effluent using copper smelter slag

This study investigated the use of copper smelter slag for the removal of phosphorus from secondary wastewater effluent through batch tests. The media was physically and chemically characterized and showed presence of Fe2O3 (45.22%), SiO2 (14.98%), Al2O3 (3.21%), CaO (1.99%), SO3 (1.77%) and MgO (1.33%). Scanning electron microscopy monographs revealed smooth and flat surface and no heterogeneity on the surface of the slag with visible micro pores before the experiment and less visible after the experiment. The point of zero charge of the media was 5.0. Equilibrium was reached after 4 h at 29.5 ± 0.71% phosphorus removal efficiency and media dosage of 0.4/100 mL. The kinetic data was best described by Pseudo second order equation. More than one mechanisms were involved in the adsorption of phosphorus onto copper smelter slag as suggested by multi-linearity of intra particle diffusion model. Ninety seven percent (97.5 ± 0.0%) removal efficiency was achieved at an equilibrium dosage of 160 gL-1. The equilibrium isotherm was described better by Langmuir equation with observed maximum adsorption capacity of 0.16 mg P g-1 media and the experimental maximum adsorption capacity was 0.26 mg P g-1 media. Regeneration studies showed low performance with maximum efficiency of 11.7% revealed during the first regeneration trial therefore low practical benefits. Copper smelter slag is a poor adsorbent for phosphorus and further studies on the media should be conducted.

Improvement of Ultrafiltration for Treatment of Phosphorus-Containing Water by a Lanthanum-Modified Aminated Polyacrylonitrile Membrane

Phosphorus contamination in fresh water has posed a great risk to aquatic ecosystems and human health due to extensive eutrophication. In this paper, we are reporting a lanthanum (La)-modified aminated polyacrylonitrile (PAN) adsorptive membrane for effective decontamination of phosphorus from the simulated water. The PAN membrane was first aminated to introduce the amine group as an active site for La and then followed by the in situ precipitation of La particles. The kinetics study showed that the rapid adsorption occurred within the initial 4 h with the equilibrium established at 8 h. The membrane worked well in the acidic pH region, with optimal pH 4 and 5 without and with the pH control, respectively. The maximum adsorption capacities were 50 and 44.64 mg/g at pH 5 and 7, respectively. The adsorption of phosphorus was not affected by the existence of commonly existing anions except fluorides in water. In the filtration study, it was observed that the removal of phosphorus remained the optimum, although the operating pressure was increased from 1 to 3 bar. The modified membrane was able to treat 0.32 L of a 10 mg/L phosphate solution to meet the maximum allowable limit of 0.15 mg/L for the trade effluent. The mechanism study revealed that the removal was primarily associated with the ion exchange between a phosphorus ion and a hydroxyl group from the La particles.

Recovery of phosphate from aqueous solutions using calcined eggshell as an eco-friendly adsorbent

Phosphorus scarcity has become a significant issue in the European Union (EU) during 21st Century, due to its relevance as an irreplaceable macronutrient for life, and because of the total dependency of EU regarding imports. This work aims to evaluate the phosphorus recovery by adsorption in batch and fixed-bed column, using a thermally modified eggshell as an adsorbent. The screening phase revealed that calcined eggshell at 700 °C (CES700) is the most suitable material compared with the other thermally modified eggshells tested. Thus, CES700 was characterized regarding the specific surface area, pore volume, zero-point charge pH, total dissolved solids and organic matter. The influence of pH and adsorbent dosage was investigated in batch conditions. Langmuir-Freundlich model described the equilibrium data and the maximum adsorption capacity was about 39 mg P-PO₄/g. The kinetics follows a pseudo-first order model, with constants between 0.063 and 0.224 min^-1. Fixed-bed studies indicated that increasing fluid superficial velocity and feed concentration led to an early saturation of the adsorbent. Yoon-Nelson, Thomas and Bohard-Adams empirical models properly adjusted the breakthrough curves with R² ≥ 0.98. Germination tests using CES700 loaded with phosphate revealed a germination index of 120 and 124% to 48 and 72 h, respectively. CES700 is statically better than the other tested materials, which opens the possibility of its use as fertilizer. This study showed that the developed material, CES700, can be applied in batch or fixed-bed processes to recover phosphate ions from liquid effluents, and the loaded adsorbent has potential to be further used as fertilizer.

Adsorption of phosphorus by using magnetic Mg-Al-, Zn-Al- and Mg-Fe-layered double hydroxides: comparison studies and adsorption mechanism

Mg-Al, Zn-Al and Mg-Fe magnetic layered double hydroxide (LDH) adsorbents were synthesized. The adsorption effect and influencing factors of these adsorbents were explored, and the adsorption mechanism of phosphorus was studied with advanced instruments. The results showed that the best adsorption performance was observed when the molar ratio of metals was 3 for the magnetic LDH adsorbents, and the maximum adsorption amount for phosphorus was 74.8, 80.8 and 67.8 mg/g for Mg-Al, Zn-Al and Mg-Fe LDHs, respectively. Pseudo-second-order kinetics could be used to describe the adsorption process of phosphorus onto the magnetic LDHs. The adsorption of phosphorus onto the magnetic LDHs was an exothermic process. Lower temperatures were favourable for adsorption, and the adsorption of phosphorus onto the magnetic LDHs was a spontaneous process. When the solid-liquid ratios were 0.10 g/L, 0.10 g/L and 0.05 g/L for Mg-Al, Zn-Al and Mg-Fe magnetic LDHs, respectively, the highest adsorption amount of phosphorus was achieved for each magnetic LDH. The maximum adsorption amount was observed at pH values of 6.0-8.0. The inhibitory effect of HCO₃^- on the adsorption capacity of phosphorus onto the magnetic LDHs was the strongest at a higher HCO₃^- concentration level. The relative content of -OH significantly reduced after adsorption of phosphorus by the FTIR analysis, which indicated that the mechanism of phosphorus removal was mainly through the exchange between hydroxyl on the adsorbent surface and phosphorus in water. XPS studies showed that oxygen provided electrons during the adsorption of phosphorus.

Calcined Eggshell as a P Reactive Media Filter-Batch Tests and Column Sorption Experiment

The goal of the study was to assess the sorption properties of calcined eggshells (CEs) as a P reactive media filter. The CEs were calcined in a temperature of 900 °C. A double stage test was performed: batch studies (kinetic and equilibrium) and small-scale column experiment. The estimation of optimal mass ratio of CEs for perspective usage was the additional benefit of column experiment. The short kinetic tests showed that 5 min of contact time with solution of initial concentration of 6.020 mgP-PO₄ L^-1 is enough to reduce the P-PO₄ in 100%. The equilibrium studies were conducted with P-PO₄ solution of 6.020 to 977.7 mg L^-1 with contact time of 30 min. The obtained data was compensated by non-linear regression using the Marquardt algorithm in the Statgraphics Centurion XVI. The eggshell calcined characterized by high sorption capacity (S _max = 72.87 mg g^-1) obtained from the Langmuir isotherm model with a good fit (96.77%). To choose the appropriate ratio of a sand filter to eggshells amendment, four small columns were constructed and fed with P-PO₄ solution (C _in ≈ 5 mg L^-1). The percentage mass (m/m) of CEs in the columns was 0.0 (the reference one); 1.0; 2.5; and 5.0. The unit sorption obtained during 95 days of column experiment was 10.668, 4.277, and 2.286 mg P-PO₄ g^-1 for 1.0, 2.5, and 5.0%, respectively. For practical implementation, the most recommended addition seems to be 1% of CEs. It corresponds, e.g., to the mass of 49 kg CEs for septic tank system.

The use of calcium carbonate-enriched clay minerals and diammonium phosphate as novel immobilization agents for mercury remediation: Spectral investigations and field applications

We used calcium carbonate-enriched clay minerals (CECM) and diammonium phosphate (DAP) as immobilization agents for mercury (Hg) immobilization. The effects of CECM, DAP, or both in different amounts and ratios, as well as pH and initial Hg concentrations, on Hg removal from solutions were investigated. The removal mechanism was revealed using transmission electron microscope with energy-dispersive X-ray (TEM-EDX) spectroscopy, and extended X-ray absorption fine structure spectroscopy (EXAFS). The performance of CECM and DAP under field conditions was also studied. The results showed that application of CECM and DAP at a ratio of 50:1 (w/w) removed over 90% of Hg from solutions containing 1.8 μM Hg²⁺, which was 9- or 2.6-fold higher than solely DAP (<10%) or CECM (34%<), respectively. Mercury removal by CECM and DAP was weakly affected by pH values between 4 and 10, and their maximum Hg removal capacity was 37 mg g^-1. Both TEM-EDX and EXAFS results showed that the precipitate of Hg with phosphorus-associated minerals might be the primary mechanism of Hg removal by CECM and DAP. Results from the field trial showed that application of CECM and DAP decreased soil bioavailable Hg contents, but did not affect contents of organic matter bound Hg or residual Hg fractions, as compared with control and initial soils. Application of CECM and DAP resulted in dramatic reductions (40%-53%) of Hg in the edible tissues of Brassica chinensis and Raphanus raphanistrum in comparison to the non-treated control. We conclude that CECM and DAP offer a promising method for in situ remediation of Hg-contaminated farmlands in southwest of China.

'Agricultural Waste to Treasure' - Biochar and eggshell to impede soil antibiotics/antibiotic resistant bacteria (genes) from accumulating in Solanum tuberosum L

Soil contamination with antibiotics and antibiotic resistant bacteria/genes (ARB/ARGs) has becoming an emerging environmental problem. Moreover, the mixed pollutants' transfer and accumulation from soil to tuberous vegetables has posed a great threat against food security and human health. In this work, the application of two absorbing materials (maize biochar and sulfate modified eggshell) was able to reduce the poisonous effect of soil antibiotics on potato root system by stimulate the dissipation of water-soluble antibiotics in soil; and also improve food quality by increasing potato starch, protein, fat, and vitamins. Meanwhile, both amendments could effectively decrease the classes and the accumulative abundance of ARB and ARGs (sulI, sulII, catI, catII, ermA, ermB) in the edible parts of potato. The lowest abundance of ARGs was detected in the biochar application treatment, with the accumulative ARG level of 8.9 × 10² and 7.2 × 10² copies mL^-1 in potato peel (sull + catI + ermA) and tuberous root (sulI), respectively. It is the first study to demonstrate the feasibility of biochar and eggshell derived from agricultural wastes as green absorbing materials to reduce soil antibiotic, ARB, and ARGs accumulation risk in tuberous vegetable.

Investigation of Taguchi optimization, equilibrium isotherms, and kinetic modeling for phosphorus adsorption onto natural zeolite of clinoptilolite type

Adsorption process plays an important role in the removal of phosphorus from aqueous solutions. A laboratory experiment was conducted to investigate the adsorption characteristics of phosphorus onto natural zeolite and to find out the relative importance of some controllable treatments in phosphorus adsorption process using the Taguchi optimization methodology. Results showed that the adsorption of phosphorus in the presence of Fe3+ and Al3+ was higher than that in the absence of these two cations probably due to the adsorption of phosphorus-bearing anions on opposite charges of these cations. Also, increase in contact time tended phosphorus adsorption to be increased. The addition of base and acid treatments caused an increase and a decrease, respectively, on phosphorus adsorption. The order of effectiveness of treatments on the values of phosphorus adsorption was as follows: acid/base treatment >sorbent to sorbate ratio > modification with aluminium (Al)/iron (Fe) >contact time >phosphorus concentration. Phosphorus adsorption data well fitted to the Freundlich isotherm model. The pseudo-second order was the best model describing phosphorus adsorption kinetics. According to the results reported herein, it is assumed that the main mechanism controlling phosphorus adsorption onto natural zeolite is chemisorption.

Statistical optimization and batch studies on adsorption of phosphate using Al-eggshell

This work provides a simple and convenient method to manufacture the sorbent of Al-eggshell. The influence of AlCl3 concentration and pH values as well as the dosage of sorbent and their interactions on adsorption of phosphate was investigated. Therefore, Box–Behnken design coupled with response surface method was adopted to explore the empirical model for phosphate species removal. It was observed that there is an optimal point, C(AlCl3)(0.29 mol/l)–pH(6.12)–dosage(6.72 g/l), for the goal of maximizing phosphate species removal. The second-order polynomial model for phosphate reduction was given as Removal(%) = 96.43 +10.82X1 + 4.29X2 − 0.70X3 + 2.06X1X2 − 1.72X1X3 +8.24X2X3 − 13.10X12 − 17.26X22 − 1.72X32. Contour pictures implied that the interaction between pH values and sorbent dosage was the strongest, followed by C(AlCl3) versus dosage and C(AlCl3) versus pH. The adsorption of phosphate data had a good agreement with the Freundlich isotherm equation at 313 and 323 K. Otherwise, Langmuir–Freundlich model described the best fitness at the temperature of 293, 298, and 303 K. The process of adsorption of phosphate on Al-eggshell fitted a pseudo-second-order kinetic equation, which indicates the exothermic reaction. In conclusion, the present work suggests Al-eggshell as an efficient and environmental friendly sorbent for phosphate species adsorption from aqueous solutions.